If in doubt, compare it to sex.

A willing subject will probably have a nice, euphoric time. An unwilling subject would feel violated and assaulted.

It also depends on the circumstances, and what crazy psychadelic vampire mind influence they're under. Most vampires would, quite instinctively, repress the subject's capacity to feel pain, and either make them drowsy (the rapey kind) or have them on a high (the nice drunk-sex-after-a-third-date kind).

Since vampires are totally a thing now, it's easy to find information on (a) how not to kill the subject and (b) how to tend to to the wound. It can be done quite safely.